O King, by the passing of time, land and other material possessions are purified; by bathing, the body is purified; and by being cleansed, unclean things are purified. By purificatory ceremonies, birth is purified; by austerity, the senses are purified; and by worship and charity offered to the brāhmaṇas, material possessions are purified. By satisfaction, the mind is purified; and by self-realization, or Kṛṣṇa consciousness, the soul is purified.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
कालेन स्नानशौचाभ्यां संस्कारैस्तपसेज्यया । शुध्यन्ति दानैः सन्तुष्ट्या द्रव्याण्यात्माऽऽत्मविद्यया
kālena snānaśaucābhyāṃ saṃskāraistapasejyayā | śudhyanti dānaiḥ santuṣṭyā dravyāṇyātmā''tmavidyayā
SB 10.5.4